When you join LinkedIn, you create a profile (similar to an online resume) that summarizes your professional experience and accomplishments. You then use your profile to connect with people in your network. Your profile is how you get found on LinkedIn by potential employers.
Once you sign-up for LinkedIn and create a profile you can start to build a network of contacts, including people you are connected with on a professional basis, an educational basis, or based on another common interest.
LinkedIn members can search for jobs, join groups, research companies, and networking with members of their network.
Companies can post information about the company and job listings on company pages.
How to Use LinkedIn